Regenerative Grazing's Accounting Trick
2 Oct 2023
It’s been reported more and more that farming cows for beef can have negative effects on climate change [1]. The cows burp and fart methane, so goes the argument, which is a potent greenhouse gas (GHG). Forests are burned down for pastureland and land to grow crops fed to farm animals, releasing even more carbon dioxide (CO2). People like eating beef, they like having a climate hospitable to humans too…
Regenerative grazing promises humans to have their climate and eat their beef too. It is a novel approach to farming cows, as well as other grazers, that promises to reduce climate impact. Mostly by restoring grasslands that cows graze which absorbs so much CO2 that the cows’ methane emissions are offset, or dramatically reduced. In this post, we’ll look if this promise can ever deliver carbon-guilt-free beef on our plates.
Effects
All in all, unfortunately regenerative grazing doesn’t produce climate neutral beef. Even worse, while it is less bad than conventional factory farming when typical conversion rates are used for methane and CO2, these are unrealistic here. Regenerative grazing is likely to be worse for GHG emissions than conventional factory farming in the long term.
Definition
Regenerative grazing is no formally defined term, it covers multiple methods that can be different depending on the environment they are deployed in. What they have in common is that these techniques are used to maximise the soil’s resilience. They are inspired by how herds of cows, bison and other ruminants historically migrated, grazing intensely on a small patch of land for a short amount of time, before moving on. This leaves the grassland alone in between being gazed so it can recover more naturally. [2][3]
Side Note
Even if regenerative grazing would one day provide climate guilt-free beef at scale, this is no reason to not drastically cut down your consumption of beef from traditional and factory-farmed sources today. Meanwhile, established interests are already trying to capture the term “regenerative” to keep the current ways acceptable. E.g. this article from the University of Oxford [9] is open about this:
Proposed solutions range from ‘clean-cow’ sustainable intensification to ‘no-cow’, animal free futures, both of which encourage a disruptive break with past practice. This paper reviews the alternative proposition of regenerative agriculture that naturalises beef and dairy production by invoking the past to justify future, nature-based solutions.
When regenerative grazing is used to get people to continue to buy more factory farmed meat like this, its promise is spoiled before it's started.
Land use
Before we dive into the GHG calculation, let’s confirm a known limitation. Regenerative grazing cannot sustain the same number of animals and productivity. On the same amount of land productivity drops to 40-50% of conventional farms. This means 2-2.5x the amount of land is needed for such an approach. Which is a serious issue, beef and lamb/mutton are already the biggest land users by far today, even when measured on protein [4].
Direct emissions and absorption
Grass fed and fully pasture raised cows grow slower and to lower weights. During this extra time, they emit more methane than cows raised with the conventional method. Because of this, regenerative grazing emissions are higher than conventional systems before soil regeneration is included.
Taking this soil sequestration into account produces wildly differing result. From almost no effect (4% reduction)[2] to over 100% showing a net positive effect on a short timeframe [5]. It is worth noting that the authors of the latter study expected the benefits to drop going forward. Longer time range studies report between 20-66% benefit over the conventional approach [3] [6].
Taking the longer time frames into account is essential. Soils that are recovering will sequester a lot of CO2 in the beginning, but taper off and eventually stop sequestering as they approach the point where they have recovered. The exact time varies, taking the measurements from this study [10], I estimate that two or three decades is a likely typical recovery time.
Clever Accounting
This brings us to the accounting trick. First, look at how methane and CO2 heat the earth in different ways. Methane does a lot of heating in a short amount of time before it breaks down into CO2 itself. This means that when you compare the heating of methane and CO2 at a short timescale you find a higher number than when you look at a very long timescale. For this, scientists typically use “CO2 equivalent over 100 years” as a decent balance between short and long term. The benefits we found above, from 4% to over 100%, all use the 100 years number.
Second, add that regenerative grazing can sequester CO2, but only temporarily until the soil is recovered. This takes 20 to 30 years approximately, not 100. This is the accounting trick. Spreading the methane heating “costs” out over 100 years, while only sequestering for at most 30, makes regenerative grazing look far more favourable than it should. Especially as sequestration drops of near the end of that 30 years.
How could we properly account for this? We can use methane’s CO2 equivalent number for 20 years. This is about 3.5x higher than for 100 years, wiping out any benefits and being worse than conventional farming!
Alternatively, we could ensure the carbon, once sequestered stays in the soil for at least 100 years. The regenerative farmer could buy a new degraded plot of land after the first one is restored and must also keep the original one to ensure it is untouched. Then after the second plot is restored buy a third and keep the second plot, etc. This adds to the already higher costs and multiplies the already very high land use by at least 3, probably more. This is probably an unacceptable cost for an estimated 20-66% reduction in emissions.
Either way, without this accounting trick the numbers just don’t work in regenerative grazing's favour.
What to do instead?
The final nail in the coffin of regenerative grazing is availability of the alternative: Eat less beef or, ideally, none at all. Changing from eating beef to plants dramatically reduces the land required. On top of that, simply leaving this, mostly, degraded land alone restores and sequesters CO2 as well [7]. All without emitting any methane that has to be compensated for a certain beneficial effect. This sequestration offsets about 16 years of global CO2 emissions instead of clearing more forest for pasture and animal feed crops [8]. On top of that, such a dramatic reduction of the number of cows on the planet also reduces the methane being emitted. Uniquely, methane’s shorter lifespan in the atmosphere would have a cooling effect quickly, after a decade already. We may not eat our beef, but we can at least have our climate.